Living on a ball

[ethelthefrog]

On a thread on garpu's journal, I was discussing great-circles. It also became apparent that Cambourne is pretty much the same distance from Los Angeles as it is from Seoul (approx 5450 statute miles). Far from obvious if you look at a flat (Mercator or similar) map of the world.

So anyway, I fired up Google Earth and drew a couple of lines.

Comments

[kjaneway]

Generally, though. It's flown via Chicago, unless, I suppose, you've got lucky and picked up one of the non-stop flight.

[garpu]

Makes everything look so small, doesn't it?

[ethelthefrog]

Yeah. Yeah.

So, can we have your liver, then?

[garpu]

Yeah sure. I'm not using it at the moment.

[gerald_duck]

The routes aircraft take are also influenced by coriolis forces, I thought, or do you count those as meteorological?

One of my favourite factoids about great circles is there are parts of the USA more distant from Washington DC than London is.

[ethelthefrog]

Depends on what you're meaning. If you mean the effect of the Earth's rotation on the plane itself, that is going to be very small, as the aircraft is small in extent and fast moving. If you mean the effect on the air that the plane is flying through, it's a meteorological force in this context.

[gerald_duck]

I mean the effect that, once the plane is in the upper atmosphere, it is less constrained to spin as part of the Earth's frame of reference which, relative to the Earth, helps Westward travel and hinders Eastward more near the equator than the poles.

The reason I say it might count as a meteorological effect is that the upper-atmosphere air currents are doing pretty-much the same thing as the plane for pretty-much the same reason.

re: factoids

[spodlife]

Do you have proof of that factoid? Alaska and Hawaii don't count.

[anonymous]

That raises the question - What's the maximum error of distance between two points on the mercator projection?